RESUMO
Objective To investigate does intracellular protein degradation pathway play an important role in decrease of endothelial nitric oxide synthase (eNOS) in human umbilical vein endothelial cells (HUVECs).MethodsTo establish a primary HUVECs culture methods,the HUVECs were incubated with concentration gradient group of TNF-α(0.01,0.1,1 and 10 ng/mL) in different time periods (24,48 and 72 h).The HUVECs were pretreated with NH4Cl or treated with caspase inhibitor or MG-132 1.5 h prior to incubation for an additional 24 h with TNF-α.The expression of eNOS was detected via Western blot assay.Results Treatment of the HUVECs with TNF-α(0.01-10 ng/mL) led to a dose-dependent reduction of eNOS expression.And treatment with TNF-α(1 ng/mL) reduced the eNOS expression in a time-depended manner.Compared with the TNF-α group,the protein expression level of eNOS was obviously increased in the co-working group of MG-123 and TNF-α.Conclusions TNF-α induces degradation of eNOS through a ubiquitin-proteasome pathway.